Update and a few questions (Convergence Problems - VS-55601 55 in Projection)

Question (see below for more details):
The big question I have is this: If the convergence chip went bad, why would the TV exhibit the convergence problem, then have it go away for a day, then come back again? I would think once it goes bad it would stay bad? The problem was immediate upon turn on, then I turned it off for 10 minutes, back on and everything was back to normal (and for several hours that night). Then the following day and ever since, the problem is back.
Thinks I tried:
I removed the convergence board (disconnecting all connections) and found the following:
1. No resistors were burned, no overheat marks, and all the pins on the SK convergence chips looked ok.
2. I saw that one resistor and 2 pins on the VGR connector had flux near them (assuming this means someone had replaced these in the past). By tracing the solder traces these seem to be related to the center convergence chip and trace to the VGR connetor (assuming this is for the green convergence).
3. I removed (solder) and resoldered all the main resistors and flowed clean solder on them. I also reflowed the solder to all pins on the center convergence chip.
4. I tested all large resistors and read consistant values for each (1.7 ohm, 4.5 ohm, and 0.555 kOhm)
5. On powerup, I jiggled all connectors to the convergence card and the corresponding connectors on the yoke of the green tube (carefully!). I also adjusted the screen and focus for the green tube (worked fine).
None of the above changed the result. I still have convergence issues with the green tube and *only* in the vertical direction.
I spoke with a local tech friend who said something about each chip has vertical and horizontal convergence sections and there are separate sections per color (he said 2 chips: 1 vert 1 horizontal, then 3 colors per chip, but doesn't work on Mitsubishi's). From what I can tell this is 3 chips (1 per color) and guessing each chip has vert and horizontal sections.
Is the above correct? If so it would seem the chip could be bad for the vertical section.
The big question I have is this: If the chip went bad, why would the TV exhibit the problem, then have it go away for a day, then come back again? I would think once it goes bad it would stay bad?
I may order the chip and just replace it and see if anything changes, given I am dreading any manual convergence after replacement.
Is there a good source for these chips? The chip is an STK-391-020.
Thanks for all the help! :)
Buzz

1 Answer

Yes, they go bad interment because they have a large current go thru them and they generate heat, they are mounted on a heat sink with white silicone to help disapate heat. replace both not just one, try MCM Electronics get heat sink compound also

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Projection TV sets are known to have two common problems. The first problem that is common to these sets is convergence failure. When this happens the TV will usually look 3D, Wavy/Distorted, etc. It may also shutdown and blink an error code.

The second common problem with Projection TV sets is dull video, halos around objects, white looking video, or red overpowers the screen. This is commonly caused by the fluid in the lens being clouded over.

The most likely cause is shorted convergence chips and possibly a few pico fuses.

These sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the picture to look normal. This is called convergence.

When its out of alignment the video will look 3-D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired. Convergence problems are very common on all Projection TV sets including Sony,Samsung,JVC,Philip Magnavox,Panasonic,Akai,Pioneer Hitachi,Mitsubishi,Zenith and others. You can get a convergenece repair kit with instructions from the links below.

Replacing the whole board will fix it, but is a bit of overkill. If you can solder and feel comfortable working inside the set, you can fix this yourself. Let me know if you wish to attempt the repair and I'll proviode additional details and instructions.

You have 2 distinct problems that should be addressed separately. Please repost the Samsung problem. I will address the Sony problem here.

If the "shadow" makes the picture seem somewhat of a 3D one, the problem is with the convergence circuit. This could be as simple as bad connections on the pins of the convergence ICs or defective ICs. If you can solder and would like to attempt the repair, update this and I'll provide more details and instructions.

Projection TV sets are known to have two common problems. The first problem that is common to these sets is convergence failure. When this happens the TV will usually look 3D, Wavy/Distorted, etc. It may also shutdown and blink an error code.

The second common problem with Projection TV sets is dull video, halos around objects, white looking video, or red overpowers the screen. This is commonly caused by the fluid in the lens being clouded overs.

You can find more details and solutions here on Fixya at the following link below. Or click HERE

I believe I have a convergence problem with my VS-45605, i cannot get the front panel controls to move the blue and red crosses. I dont have original remote and a universal remote doesnt work either, any suggestions.

This sounds like convergence amps not vertical, what was the set doing prior? If convergence amps first check: E2RESET DOES NOT RESET THE CONVERGENCE. THE CONVERGENCE CAN BE RESET BY PRESSING "MENU 12598970", IF THIS DOES NOT RESET THE CONVERGENCE TRY "MENU 125968970